Effects of acute stretching on the maximal expression of strength

P Nongogo, B S Shaw, I Shaw

Abstract

Stretching exercises are commonly used as an integral part of a pre-exercise warm-up training sessions despite even early laboratory studies having demonstrated that some degree of mechanical weakness takes place following the stretching of muscle tissue. This study compared the effects of four treatments (n = 12 each) [10 minutes of quiet sitting, without stretching (NS); two minutes warm up on an arm ergometer at 25 watts resistance (WU); 10 second-hold static stretching (each) of the shoulder, chest and arm muscle groups (ST10); and two sets of 20 second-hold static stretching (each) of the shoulder, chest and upper-arm muscle groups (ST20)] on a 1-RM bench press in 48 subjects who were matched for their pre-test 1-RM bench press values. The mean 1-RM bench press values following ST10 (45.0 ± 9.9 kg) and WU (48.9 ± 10.5 kg) treatments were significantly (p ≤ 0.05) higher at the post-test than at the pre-test 1-RM (43.9 ± 10.1 kg and 43.9 ± 10. kg, respectively). The mean 1-RM values following the ST20 treatment was significantly lower (41.9 ± 10.0 kg) than at pre-test (43.9 ± 10.1 kg). However, multiple comparisons and Analysis of Variance (ANOVA) statistical procedures demonstrated that there was no significant difference from pre- to post-test between the four groups. These findings suggest that the use of stretching activities prior to events requiring maximal force production may not be obligatory or may even be contraindicated since the effects of stretching are then to decrease the amount of force that can be produced via the natural elastic components of the muscle and tendons and via the stretch reflex.